Very Slow Screen Refreshing

You know how it goes. visit the family this time of year and you hear, "While you are down here, don't suppose you could look at this computer could you?"

Anyway, the problem with the computer I got given is that whilst using Windows, any time you open/close a window, scroll anything, or just move something in general, the screen takes about a second to refresh. I can actually see the lines being drawn down the screen. I have a clean install of Windows (it originally crashed just going into Safe Mode at first, so had to re-install) and noticed the problem during install when selecting languages etc..

Of course, drivers were the first port of call, with both MB and graphic's drivers being installed. However, the graphic's caused there to be no display as Windows started (as though it was an unrecognisable resolution), so had to disable that. I've swapped the graphics card into my machine and seems to work perfectly. I put a different card into the duff machine and the results were exactly the same as before, so that rules out the card.

I was told that the machine was working fine until it started doing this "one day". It is also being used by a 12 year-old kid as well, so I'm have convinced they've done something to it either physically or software wise, but the clean install of Windows rules out software though.

It was built by Novatech, but the warranty has long run out. The specs are:-

I'm stumped as to what is causing the problem. It's like the card is being throttled heavily. Nothing seems out of place in the BIOS. I am guessing MB. CPU-Z reads the CPU and RAM as OK and running as normal speeds.

Received thanks from:

Re: Very Slow Screen Refreshing

Originally Posted by arthurleung

Look in Display Properties -> Advance -> Troubleshoot and see if the Acceleration was turned down?

No, it wasn't. In fact, when I turned it down right down, it performed much better; just at 640x480and 4bit colours (VGA mode I presume).
There is no PCI-E power connector on the the 6600GT. I might try swapping the PSUs around to eliminate another part of the system as the cause. I'll also look into the Event Logs while I'm at it later on today.

Re: Very Slow Screen Refreshing

Well, after much troubleshooting, I'm putting it down to the MB.

Swapped the PSU with a bigger and better one; no change.
Swapped the memory out and replaced with a matched pair; no change.
Swapped hard drives (mainly to stop my Dad from nagging ); no change.
Swapped the 6600GT with a PCI GeForce 2 to check the PCI-E slot wasn't the probelm. Same problem, but quicker; i.e. I can still see the lines refresh, but it's now 2-3 times quicker. Seems to be the less powerful the card, the smoother the image.
Checked the Event Viewer, and saw no problems. Disabled everything onboard (LAN, Audio etc. There is no onboard video.) just to reduce the chance of conflicts, but still no change.

So that just leaves the MB and CPU. I'm going to rule out the CPU as the BIOS, Windows and CPU-Z don't show any problems. I am guessing there might be a problem with the south bridge. It has a fan on it and might have stopeed at some point and overheated. Very unlikely, but this thing was filthy when I got it, and the clean doesn't seemed to have improved anything. The only other slightly unusual thing I noticed was with the 4 pin Molex socket (labelled AUX PEX PWR; so guessing it's for the PCI-E slot) on the MB had some black, possibly scorch marks around one of the pins. Might be nothing, but could be another source of the problem.

Anyway, thanks for the suggestions guys, but I am just going to declare it as FUBAR. Serves them right for not getting it fixed when the problem first appeared within the warranty period...